Shallow M5.9 AFTERSHOCK struck on Monday Morning in the South Pacific Ocean 230km from Apia (Samoa).

Written by Earthquakelist.org on March 22nd, 2026. Last updated April 18th, 2026.

In the South Pacific Ocean 230 kilometer from Apia, Samoa, a shallow and significant Magnitude 5.9 aftershock occurred in the morning of Monday March 23rd, 2026. Roughly 170 thousand people may have felt this earthquake. Another country near the epicenter is American Samoa.

Earthquake Summary

This earthquake hit under water in the South Pacific Ocean, 206 kilometers (128 mi) off the coast of Samoa, 230 kilometer southwest of Apia in Tuamasaga. The center of this earthquake had a very shallow depth of 13 km. Shallow earthquakes usually have a larger impact than earthquakes deep in the earth.

Date and Time:	Mar 23, 2026 11:26 (Apia Time) - Mar 22, 2026 22:26 Universal Time.
Location:	230 km SW of Apia, Tuamasaga, Samoa. Coordinates 15°37'52"S 172°49'6"W.
Map:	Map of area around epicenter. Click to open in Google Maps.
Magnitude:	MAG 5.9 Detected by 13 stations. Maximum Error Range ±0.058 .
Depth:	13 km (8 mi) A very shallow depth.
Max. Intensity:	IV Light On the Modified Mercalli Scale.
Tsunami Risk:	Low tsunami risk Earthquakes under MAG-6.5 do not usually cause tsunami's. Always stay cautious - More info here.

Minimal impact predicted

Based on scientific estimates by the US Geographic Survey (USGS), the risk of high fatalities for this earthquake is classified at level GREEN (low). They expect an 90% likelyhood of between 0 and 1 fatalities.

The USGS classifies the economic impact of this earthquake at level GREEN (low). They expect an 90% likelyhood of between 0 and 1 million US Dollars in economic damage and impact.

Roughly 170 thousand people exposed to shaking

The USGS has published a report estimating the number of people exposed to this earthquake. Acoording to their analysis, roughly 170 thousand have been exposed to shaking at an MMI level of II or higher.

An estimated 164,600 people were exposed to level III. At this level, weak shaking and probably no damage can be expected.

People in 2 countries have been exposed to shaking. Roughly 170 thousand people were exposed to shaking in Samoa , with level III (weak shaking, probably no damage) as the highest recorded.

People	MMI Level	Shaking	Damage
0	I	Not noticable	None
640	II	Very weak	None
164,600	III	Weak	Probably none
0	IV	Light	Likely none
0	V	Moderate	Very light
0	VI	Strong	Light
0	VII	Very Strong	Moderate
0	VIII	Severe	Moderate to heavy
0	IX	Violent	Heavy
0	X	Extreme	Very heavy

Nearby towns and cities

This earthquake struck within proximity of multiple countries. Samoa and American Samoa are both within 300km distance of its epicenter.

Located 230 kilometer (143 mi) southwest of the epicenter of this earthquake, Apia (Tuamasaga, Samoa) is the nearest significant population center. The intensity of shaking and damage in Apia is estimated to be around level III on the Modified Mercalli Intensity scale (weak shaking, probably no damage).

Overview of nearby places

Cities and Towns around the epicenter of this earthquake.
Distance	Place	Intensity (MMI)
230 km (143 mi) NE from epicenter	Apia Tuamasaga, Samoa.	III Weak
273 km (170 mi) NE from epicenter	Pago Pago Eastern District, American Samoa.

Earthquake Intensity Map

The intensity in shaking and damage by this earthquake is illustrated through the map below. The highest intensity measured for this earthquake is IV.

I Not felt

II Weak

III Weak

IV Light

V Moderate

VI Strong

VII Very Strong

VIII Severe

IX Violent

X Extreme

Earthquake Intensity Map based on Shakemap Data provided by USGS.

This is likely an aftershock

This earthquake was an aftershock. A larger mag. 6.3 earthquake struck 37 km (23 mi) north-east in advance of this 5.9 earthquake around 7 hrs earlier.

Overview of foreshocks and aftershocks

Detected MAG2.5+ earthquakes within within 100km (62 mi), that occurred in the three days before and after the main shock.
Classification	Magnitude	When	Where
Foreshock	M 4.4	9 hrs earlier Mar 22, 2026 19:07 (Apia Time)	35 km (21 mi) NW from Main Shock.
Foreshock	M 6.2	9 hrs earlier Mar 22, 2026 19:15 (Apia Time)	37 km (23 mi) NW from Main Shock.
Foreshock	M 4.4	9 hrs earlier Mar 22, 2026 19:31 (Apia Time)	49 km (30 mi) W from Main Shock.
Foreshock	M 4.4	9 hrs earlier Mar 22, 2026 19:36 (Apia Time)	34 km (21 mi) N from Main Shock.
Foreshock	M 4.4	8 hrs earlier Mar 22, 2026 20:11 (Apia Time)	27 km (16 mi) W from Main Shock.
Foreshock	M 4.5	5 hrs earlier Mar 22, 2026 23:57 (Apia Time)	55 km (34 mi) W from Main Shock.
Foreshock	M 4.6	1 hr earlier Mar 23, 2026 03:08 (Apia Time)	15 km (9 mi) E from Main Shock.
Foreshock	M 6.2	3 mins earlier Mar 23, 2026 04:27 (Apia Time)	12 km (8 mi) NE from Main Shock.
Foreshock	M 6.2	3 mins earlier Mar 23, 2026 04:27 (Apia Time)	37 km (23 mi) W from Main Shock.
Main Shock	M 6.3	Mar 23, 2026 04:30 (Apia Time)	-
Aftershock	M 5.6	30 mins later Mar 23, 2026 05:00 (Apia Time)	62 km (39 mi) NW from Main Shock.
Aftershock	M 4.8	53 mins later Mar 23, 2026 05:23 (Apia Time)	54 km (34 mi) NW from Main Shock.
Aftershock	M 4.8	53 mins later Mar 23, 2026 05:23 (Apia Time)	54 km (34 mi) NW from Main Shock.
Aftershock This Earthquake	M 5.9	7 hrs later Mar 23, 2026 11:26 (Apia Time)	37 km (23 mi) SW from Main Shock.
Aftershock	M 5.7	15 hrs later Mar 23, 2026 19:02 (Apia Time)	35 km (22 mi) SW from Main Shock.
Aftershock	M 5.0	17 hrs later Mar 23, 2026 21:44 (Apia Time)	20 km (13 mi) W from Main Shock.
Aftershock	M 4.3	20 hrs later Mar 24, 2026 00:40 (Apia Time)	49 km (31 mi) W from Main Shock.
Aftershock	M 4.6	20 hrs later Mar 24, 2026 00:58 (Apia Time)	40 km (25 mi) W from Main Shock.
Aftershock	M 4.2	21 hrs later Mar 24, 2026 01:25 (Apia Time)	41 km (25 mi) W from Main Shock.
Aftershock	M 4.2	21 hrs later Mar 24, 2026 01:27 (Apia Time)	68 km (42 mi) NW from Main Shock.
Aftershock	M 4.4	21 hrs later Mar 24, 2026 01:44 (Apia Time)	24 km (15 mi) W from Main Shock.
Aftershock	M 4.2	21 hrs later Mar 24, 2026 01:58 (Apia Time)	43 km (26 mi) W from Main Shock.
Aftershock	M 4.5	1 day later Mar 24, 2026 12:07 (Apia Time)	80 km (50 mi) SW from Main Shock.
Aftershock	M 4.4	1 day later Mar 24, 2026 12:10 (Apia Time)	86 km (53 mi) SW from Main Shock.
Aftershock	M 4.9	1 day later Mar 24, 2026 13:30 (Apia Time)	86 km (54 mi) S from Main Shock.

More earthquakes coming?

The risk of aftershocks decreases rapidly over time. Usually, aftershocks are at least one order of magnitude lower than a main shock.

It's always adviced to be cautious of the risk of a larger shock following any significant earthquake, however this risk is fairly small. There is a roughly 94 percent change that no larger main shock will follow in the days following this earthquake.

Read: How to Stay Safe during an Earthquake (cdc.gov).

Earthquakes like this happen often in the region

Earthquakes of this strength are very common in the region. In total, 24 earthquakes with a magnitude of 5.9 or higher have been registered within 300km (186 mi) of this epicenter in the past 10 years. This comes down to an average of once every 5 months.

Low tsunami risk

DISCLAIMER: We strongly suggest to closely monitor advice from local authorities with regards to tsunami risks. Our analysis is based on automatically collected data from external sources, and these might contain mistakes. In addition, earthquakes can cause landslides that may lead to a tsunami, or be a followed by another, potentially stonger, earthquake.

Based on early data it appears this earthquake was not strong enough (lower than MAG-6.5) to be likely to cause destructive tsunami's. However this earthquake appeared to have hit at a shallow depth under sea, so stay cautious and monitor advice from local authorities.

Tsunami Risk Factors

Factor	Under Sea?	MAG-6.5 or stronger?	Shallow depth?
Explanation	Almost all tsunami's are caused by earthquakes with their epicenter under sea or very near the sea. However stay cautious in coastal areas as earthquakes on land may cause landslides into sea, potentially still causing a local tsunami.	Under MAG 6.5: Very unlikely to cause a tsunami. MAG 6.5 to 7.5: Destructive tsunami's do occur, but are uncommon. Likely to observe small sea level changes. MAG 7.6+: Earthquakes with these magnitudes might produce destructive tsunami's.	Most destructive tsunami's are caused by shallow earthquakes with a depth between 0 and 100km under the surface of the earth. Deeper tsunami's are unlikely to displace to ocean floor.
This Earthquake	This earthquake appears to have struck under the sea.	Not this earthquake. This earthquake had a magnitude of 5.9. Earthquakes of this strength are unlikely to trigger a tsunami.	This earthquake occurred at a depth of of 13 km (8 mi). Earthquakes this shallow could trigger a tsunami.

Sources

Last updated 18/04/26 00:48 (). As more information on this earthquake becomes available this article will be updated. This article is automatically composed based on data originating from multiple sources.